A New York Times editorial on Saturday explains how--and perhaps why--EPA has once again ignored scientific experts in favor of politically expedient solutions: At issue were so-called fine particles, tiny specks of soot that are less than one-thirtieth the diameter of a human hair. They penetrate deep into the lungs and circulatory system and have been implicated in tens of thousands of deaths annually from both respiratory and coronary disease. The E.P.A., obliged under the Clean Air Act to set new exposure levels every five years, tightened the daily standard. But it left unchanged the annual standard, which affects chronic exposure and which the medical community regards as more important. In so doing, the agency rejected the recommendation of its own staff scientists and even that of its Clean Air Scientific Advisory Council, a 22-member group of outside experts that had recommended a significant tightening of the standards. Stephen Johnson, the agency administrator, claimed there was “insufficient evidence” linking health problems to long-term exposure. He added that “wherever the science gave us a clear picture, we took clear action,” noting also that “there was not complete agreement on the standard.” Instead of protecting those exposed to dangerous levels of soot, Johnson has chosen instead to protect the bottomline of powerful industries, which would have to spend a pretty penny to get up to standard. If EPA fulfilled its mandate to keep the air clean and the people who breath it healthy, it would choose to implement a protective standard and not wait for absolute consensus before acting. The cost of waiting for perfect information can be far too great.